Multicircuit switch



April 21, 1942. c. w. DANN MUL'I-ICIRCUIT SWITCH Filed Nov. 15, 1939 Charles 1111761212 Cittorneg 23 Wlhlmin Patented Apr. 21, 1942 UNITED STATES PATENT OFFICE MULTICIBOUI'I. SWITCH CharlesW.Dann, EastOnm,N.-J.,anignorto Thomas A. Edison, Incorporated, West Orange, N. 1., a corporation of New Jersey- Application November 15, 1939, Serial No. 304,514

13 Claims.

This invention relates to improvements in multicircuit switches and more particularly to Multicircuit switches of the completely shielded variety have especial utility in amplifying systems wherein there is involved the switching of circuits respectively carrying widely different oscillation levels. Such an amplifying system is typically represented in an electrical phonograph of the universal (i. e., of the combined recording and reproducing) type. In these universal phonographs the recorder and reproducer, and the microphone and speaker, may respectively be in the form of unitary devices, and the conditioning of the phonograph may be effected by switching the input and output circuits of the amplitier between these unitary devices. Because of the high gain oi such amplifiers the switching circuits must be substantially completely electrostatically shielded from each other to prevent amplifier feedback. In applications where space is no controlling factor stringent requirements in intercircuit shielding of the switch may be relaxed by a wide spacing of the switch elements-i. e., by a large switch. However, in small and compact machines, as in small desk model types of commercial phonographs or dictating machines, space is an important factor and an enlargement of the switch for purposes of relaxing its shielding is not merely barred but, to the contrary, there is a requirement for an unusually small switch. Small switches of the multicircuit type must necessarily be compact. This compactness augments the shielding requirements and the difllculties in producing an economical construction of the switch.

It is an object of my invention to provide a small and improved m/ulticircuit switch which is suitable for applications such as is above described.

It is another object of my invention to provide a simple and compactly arranged multicircuit switch wherein each circuit is substantially completely electrostatically shielded from the other.

Another object is to provide a small and substantially completely shielded multicircuit switch in a form which is economical to construct and dependable in operation.

A further object is to provide a switch of the double throw variety.having one or more poles and so constructed and arranged that each closed and open circuit is substantially completely velectr'ostatically shielded throughout at each setting of the switch.

Other and allied objects of my invention will more fully appear from the following description and the appended claims.

In the description of my invention reference is had to the accompanying drawing, of which:

Figure 1 is an end view 02 a multicircuit switch in accordance with my invention, wherein there is dottedly shown some internal parts of the switch;

Figure 2 is a side view of the switch of my invention;

Figure 3 is a longitudinal section taken axially through the switch;

Figure 4 is another end view of the switch;

Figure 5 is a cross sectional view taken substantially along the line 5-5 of Figure 3; and

Figure 6 is a cross sectional view taken substantially on the line 6-6 of Figure 3.

Reference being had to the figures there will be seen a completely shielded switch connected into a group of circuits or conductors i and comprising a main or larger assembly 2 (i. e., body portion) and a smaller assembly 3 (i. e., cover portion) connected with the main assembly for relative switch-effecting movement along their adjacent sides. These assemblies are preferably circular in cross section and coaxially pivoted to one another, as shown. The main assembly 2-the assembly which connects with the group of conductors i-may well be held stationary as by a mounting of the assembly on a base 4 by way of a bracket 5, and the smaller assembly 3 may then be turned relative to the main assembly, to operate the switch, by an operating mechanism (not shown) which may be connected to the assembly 8 by way of a link 6 pivoted as at I to a. bracket 8 that is secured to the assembly.

The main assembly 2 is cylindrical in shape and adapted to insulatedly carry a multiplicity of switch contact members or pins 9 respectively connected with the conductors i and completely shielded except for their end faces 9'. In the present embodiment there are nine of these switch contact pins disposed parallel to each other and successively spaced at equal angular distances in circular arrangement about the axis of the switch. These pins are respectively held between pairs of insulating bushings II which bear from opposite sides against collars ll provided on the pins, the bushings being counterbored to receive the collars as is shown in Figure 3. The pins and bushings are held in position by bored to receive the bushings III as the plates are brought together in face-to-face relationship.

. When the plates I2 are so held together the pins 9 are rigidly held by the collars II against longitudinal movement in positions wherein their end faces 8' are preferably slightly inset/within the outer face of one of the plates I2 and the opposite end portions 9" extend beyond the other of the plates I 2. This plate and pin arrangement is seated on a chambered cylinder I4 having nine chambers or openings I5 extending therethrough and respectively aligned with the pins 9. The end portions 9" of the pins extend respectively into these openings and into insulating bushings I6 respectively fitting the openings and extending partially along the lengths thereof. The assembly of the plates I2 and cylinder I4 is held together by a center stud I1 passing through the plates and threaded into a post I8 coaxially extending through the cylinder. The plates and cylinder I4, which are adapted to provide complete electrostatic shielding around each of the pins 9 and throughout their lengths (i. e., to electrostatically intershield the pins from each other); constitute a housing section for the switch and may well be made of zinc or alumi num as by die casting.

The end portions 9" of the pins 9 are connected respectively with the conductors I, the end portions 9" being each center-bored to receive the ends of the conductors and the connection being made by soldering, Each of the conductors I are shielded, being provided for example with shields ure 3. The ends of the shields I' may be flanged I outwardly against the end walls of the bushings I6 and into contact with the inner walls of the openings i5. While the shields will normally bear against the walls of the chambers to make connection with the body of the switch this connection may if necessary be made positively as by any suitable means. It is thus seen that the shields I form with the cylinder I4 and plates I2 a substantially uninterrupted electrostatic shielding extending completely around and along each conductor and respective switch contact pin, there being exposed only th end faces 9 of the switch contact pins.

To make the connection of the conductors I with the switch contact pins 9, respectively, the braided shields I of the conductors I are pushed back over the insulation I", the cylinder I4 is disconnected from the plates I2 and the conductors I are passed respectively through the openings I5 in the cylinder and through the bushings IS. The insulation I" is then stripped back from the ends of the conductors, the conductor ends are soldered to the switch contact pins 9, and then the cylinder is returned and fastened to the plates I2. Thereafter the ends of the shields I are flanged outwardly and returned along their conductors to within the openings I5 as shown.

The end of the cylinder I4 from which the conductors I emerge is provided with a circular cover I9 which is fastened by means of a screw 20 to an extension of the post I8. In the cover I! there is a side opening I9 through which the conductors I pass. This cover serves to hold the conductors I fiat against th end of the cylinder I4, to bunch the conductors in the desired direction, to relieve the Joints between the pins 9 and conductors I from possible stress, and to clamp the cylinder I4 against the plates I2.

The movable assembly I, hereinbefore mentioned, includes a cylindrical cover 22 which overlies the face of the plate I2 where the end faces 9' of the switch contact pins appear. The cover 22 forms a substantially continuous extension of the outer boundary of the plates and cylinder, being of the same diameter as the assembly 2. The cover is provided with a central bearing 23 which embraces the stud I1 for pivotal movement thereabout, and is held on this stud by a screw 24 which threads into the stud. The inside of the cover 22 is subdivided by means of radial partitions 25 into three equiangularly spaced and sector-shaped cavities or recesses 26. When the cover 22 is mounted on the stud I1 the recesses 26 are closed by the adjacent face of the plate I2 to form respective compartments. In order that these compartments may be electrostatically shielded the cover 22 is made of a conductive material. Like the plates I2 and cylinder I4, it is preferably made of zinc or aluminum and formed by die casting.

The recesses 26 are each in angular length substantially equal to twice the angular distance between adjacent switch contact pins so that the recesses may form with the adjacent face of the plate I2 a completely shielded compartment which may respectively enclose pairs of adjacent end faces 9' of the switch contact pins as shown in Figure 1. In each of the recesses 26 there is provided a contact-bridging spring 21. These springs are clamped at one end between a pair of inner and outer sector-shaped insulating plates 28 and 29 and are riveted to the top of the cover 22 by rivets 30, the rivets being insulated from the spring by means of insulating bushings 3|. The springs 21 are v-shaped, extending radially inwardly and .then curving axially outwardly through radially extending slots 29' in the outer plates 29, and thereafter extending radially outwardly to terminate into a pair of diverging contact fingers 21'. These fingers are biased into contact with the adjacent face of the plate I2 and are adapted to bridge or interconnect pairs of adjacent ones of the switch contact pins 9. As the cover 22 is turned these contact-bridging springs 21 slide along the end faces 9' to interconnect successively pairs of adjacent switchcontact pins. For each contact-making position of the cover 22 each pair of electrical paths closed to each other is completely electrostatically shielded throughout, the paths being shielded along their lengths by the shields I, the cylinder I4 and the plates I2 and at their point of interconnection by the completely shielded compartments formed between the cover and the adjacent one of the plates I2. Likewise, for each such contact-making position of the cover 22, each open electrical path is also completely electrostatically shielded, the shielding along the length of the paths being effected in the manner just described, and the shielding at the ends of the paths-i. e., at the end faces 9'-being effected by the close fitting of portions 32 of the cover 22, which are interposed between the recesses 25,

with the adjacent face of the plates I 2. These compartment, said stationary comprisforth between such positions, the middle one of'bach such group of switch contact members will befalternately connected with its adjacent mem-.

effect asingle-pole double-throw switch- Binoetherearethreesuchgroupsof contact members and contact-bri al! springs. the switch as a whole will be of a triple- Although 1 preferably opera the switch here shown in'the manner of a multiple-pole doubletrioalcircuits,itwillbeunderstoodthatmyinventionisnotnecessariiylimitedtosuchtypeof switch as I may, for example. cause each contactillustrative and not limitative of the scope of my "invention, which I endeavor to express according to the following claims.

I claim:

l. A shielded multicircuit switch comprising a stationary housing section, a housing section adjoining said stationary section and movable along theadjacent side thereof, said sections mutually forming electrostatically shielded compartments; a multiplicity of electrostatically intershielded switch contact members fixedly mounted in said stationary section and adapted for connection with conductors leading from said section, said switch contact members having contacts included in said compartments at the said adjacent side of the section and said compartments being each adapted to include a pair of said contacts the diil'erent pairs of which are selected by moving said movable section across the adjacent face of said stationary section; and a single contact bridging member provided in each of said compartments and carried insulatedly by said movable housing section for slidably engaging said contacts to interconnect the pairs of end faces included in the respective compartments.

2. A shielded multicircuit switch comprising two assemblies abutting one another, one of said assemblies being held stationary and the other being connected thereto for movement along their adjacent sides, said movable assembly having an electrostatically shielded cavity in its said adjacent side forming with the other assembly a substantially completely electrostatically shielded As the cover I! is moved back ing electrost'atiealiv intershielded switch contact members having contacts at its said adjacent side and adapted for connection with conductors leading from said stationary assembly, .pairs of which contacts are selectively ineludable in said compartment through the movement of said movable assembly; and a single conductive bridging element carried in said compartment by said movable assembly for slidably contacting and intereonnectingthepairsofendfaoesim.

eluded in said compartment as said movable assemblyis moved.

3. An electrostatically shielded switch for a multicircuit system comprising a housing section having apertures therein; a multiplicity of switch contact members insulatedly supported by said housing section in said apertures and each having a terminal face exposed at a boundary surface of said section; metallic shielding included in said housing section and encompassing each of said switch contactmembers along the lengths thereof; another .housing section fitting said boundary surface and movable transversely thereacross; contact bridgin elements carried by said other housing section and movable, through the transverse movement of the latter, into aclective engagement with said terminal faces; and

metallic shielding included in said other housing section and encompassing each of said bridging elements, the said shieldings of the two housing sections terminating adjacent to one another to form a separate and substantially complete electrostatic shielding of each open and closed circuit of the switch.

4. A shielded multicircuit switch comprising switch contact members having contact faces and adapted for connection with lead conductors; contact bridging members movable to contact pairs of said faces selectively; metallic shielding encompassing said switch members respectively and exposing said faces; other metallic shielding encompassing said bridging members respectively, said two shieldings substantially. abutting one another and forming a separate and substantially complete electrostatic shielding of each circuit of the switch.

5. An electrostatically shielded switch comprising a housing; switch members insulatedly supported by said housing in fixed spaced relationship therewithin and each having a contact face at a boundary surface of said housing, said housing including metal shielding encompassing said switch members respectively and exposing said contact faces; a contact bridging element sup ported adjacent to said boundary surface and having portions thereof positioned for selective contact with said contact faces; a metal cover over said contact bridging element having the edge thereof substantially abutting the said metal shielding of the switch members; and means operable to control selectively the contact of said bridging element with said contact faces.

6. A shielded switch of the double-throw variety including a structure comprising a group of three contact members respectively having contact faces successively spaced at equal distances, said structure forming electrostatic shields between said contact members and exposing said contact faces; a bridging member arranged for simultaneous contact with pairs of adjacent ones of said contact faces; and means selectively movable relative to said structure to cause said bridging member to interconnect the central contact member of said group with either of the other two contact members, said means including a metallic cover encompassing said bridging member and having the edge thereof adjacent; to said structure to form a substantially complete shielding of "the circuit between the connected ones of said contact members, and further including metallic means at the sides of said cover in adjacent relationship to said structure for shielding the faces of each unconnected one of said contact members.

7. A shielded switch of the multiple-pole double-throw variety including a structure comprising a multiplicity of switch contact members respectively having exposed contact faces circularly arranged and successively spaced at equal angular distances, said structure forming electrostatic shields between said contact members and exposing said contact faces; a plurality of conductive bridging elements .arranged to interconnect pairs of adjacent ones of said contact faces, said bridging elements being successively spaced at three times the angular distance between adjacent contact faces and being unitar'ily movable back and forth along the contact faces through the distance of spacing between adjacent contact faces, whereby to interconnect the middle contact member of each group of three with either of its adjacent contact members; metallic covers encompassing said bridging elements respectively each having the edges thereof substantially abutting said structure to form a substantially comforl'ia at each circuit switching position a substantially complete electrostatic shielding of each separate circuit of the switch. I i

10. A multicircuit switch comprising a metallic cylinder provided with a multiplicity. of parallel chambers circularly arranged about the axis of the cylinder; a multiplicity of contact members insulatedly supported by said cylinder within said chambers respectively and each having an end face terminating substantially in a plane at one end of said cylinder; a metallic cover for said one end of said cylinder pivoted to the cylinder and having its inner face provided with a plurality of recesses forming shielded compartconductive bridging elements insulatedly carried plete shielding of the circuits formed between I I the metallic means of said body portion to form electrostatically shielded compartments, each of said compartments being arranged to include a predetermined number of said end faces; contact bridging means insulatedly carried in said compartments for interconnecting the end faces included respectively therewithin; and means movably connecting said cover portion to said body portion for rendering said contact bridging means movable by the cover portion into contact with pairs of said contact faces selectively.

9. A multicircuit switch comprising a metallic body portion provided with a multiplicity of apertures each terminating at a predetermined bounding surface of said body portion; contact members insulatedly supported by said body portion in said apertures respectively and each terminating in a contact face substantially at said bounding surface; a metallic cover for said bounding surface and movable transversely thereacross; contact bridging elements insulatedly carriedby said cover portion therewithin and movable by the cover selectively into contact with pairs of said end faces; and metallic partitions in .said cover interposed between said bridging elements, the edges of said partitions terminating adjacent to said body portion to in said compartments respectively and moved along said end faces by the turning of said cover to interconnect. successively pairs of adjacent contact members.

11. A shielded switch for a multicircuit system comprising switch contact members, insulating sleeves embracing said contact members, metallic means embracing said sleeves respectively and holding said switch contact members in spaced relation, said metallic means terminating substantially at one set of the ends of said contact members to expose the ends as contacts; a contact bridging element mounted for movement across said contacts into different switch positions to interconnect diifcrent pairs of said switch contact members; and a metallic shield cover for said bridging element having the edge thereof abutting the terminal face of said metallic means at each switch position whereby to form a complete electrostatic shielding of each bridging circuit made between the different pairs of switch-contact members.

12. A shielded switch comprising a metallic body having apertures in a side thereof; insulating sleeves in said apertures; switch contact pins fitting said sleeves and terminating at said side, said pins having lateral projections embraced by said sleeves whereby the pins'are held in place in the sleeves; bridging members mounted for movement across said side into contact with the ends of pairs of said contact pins; and respective metallic cover means for said bridging members, each having the edge thereof disposed adjacent tosaid side.

13. A shielded switch comprising switch contact pins having collars on their intermediate portions; a pair of insulating bushings on each of said pins abutting against opposite sides of said collars, a pair of plates in face to face relationship and having apertures therein in registering relation to receive said bushings respectively, said bushings having enlarged diameter portions at their adjacent ends and said plates being counterbored in their adjacent faces .to receive said enlarged diameter portions and hold said bushings in place; bridging members along the outer face of one of said plates controllable to contact separately the ends of said pins and interconnect the same; and metallic covers for said bridging members respectively, cooperating with said face to form a complete electrostatic shielding of the bridging circuits made between said contact pins.

CHARLES W. DANN. 

